In the smelting of iron ore, as well as other metals, complex runner systems are employed for transferring molten metal from furnaces to transfer cars known as bottle cars. Previous runner systems have consisted of series of runners extending from the tap hole of the smelting furnaces to cars positioned on the floor of a casting house. Other transfer systems have been comprised of a single runner beginning at the tap hole and then diverging into a network of side runners with each side runner going to a different one of a group of bottle cars. Other systems have had moveable runners to direct molten metal sequentially to each of a series of side runners. These runner systems have been plagued with excessive plugging and failure of the gates which control the flow of molten metal. Considerable tapping time has been lost due to these short-comings in equipment. Moreover, many previous transfer systems have required bottle cars to be maneuvered from one track to another. This, too, decreases cast house efficiency.
Other additional problems and disadvantages have been associated with previous runner systems. Currently used runner systems require large amounts of cast house floor space because runner networks of complex design are required. The runners are expensive therefore, the longer the runners the higher the expense. Moreover, the cast house must be large enough to include all of the runners.
The runners of prior systems must be cleaned between casts. This at least in part is a byproduct of the complex systems that have been used. Each branch runner is in use for a relatively short time to fill a bottle car. By the time the furnace tap is completed the first used branch has cooled to the point where some metal solidifies and residual slag is present. The slag reacts with the refractories decreasing their lives and the slag and metal necessitates the cleanup. Because of the cleanup and refractory-slag reactions runners have generally been constructed of sand or other inexpensive refractory materials. Refractory runners last only several casts and then require replacement or repair. Frequent replacement of runners is undesirable because it is expensive and time consuming. During the replacement, the smelting operation must be shut down and valuable smelting time is lost.